Electronic devices, including mobile computing and/or communication devices, are becoming smaller thereby driving the weight and size of data storage devices down, while requiring large storage capacity in the terabyte range and low power consumption. An increasing storage capacity would require the need for increased precision in tracking the movement of the read/write head.
Data storage devices, for example hard disk drives (HDDs), employ servo systems for tracking and controlling the movement of the read/write head. Conventional servo systems may employ embedded servo where the servo information runs radially across the tracks from the inner diameter (ID) to the outer diameter (OD) of the disk in a series of “servo wedges” with data. Therefore, the servo information is only detected when the read/write head moves over these servo wedges. In between the servo wedges, no servo information is received by the head.
Data storage devices also employ dedicated servo, e.g. as shown in FIG. 1, where the servo information is provided on a servo layer 104 distinct from the data recording layer 102 (in other words: data layer 102).